Motor Impairment Trends in Extremely Preterm Children: 1991-2005

Abstract

Background: There are increasing numbers of surviving children who were born extremely preterm (EP; gestational age <28 weeks) or extremely low birth weight (ELBW; birth weight <1000 g). Our objective in this study was to compare the rates of motor impairment at 8 years of age between 3 cohorts of EP and/or ELBW and term-born children to establish if motor impairment rates are changing over time.

Methods: All children born EP and/or ELBW in the calendar years of 1991-1992, 1997, and 2005 in Victoria, Australia, were recruited at birth. Randomly selected normal birth weight (>2499 g) and term-born controls were matched for expected date of birth, sex, and sociodemographic status. At 8 years' corrected age, motor impairment was defined as cerebral palsy (CP) or a score less than the fifth centile on the Movement Assessment Battery for Children for the 1991-1992 and 1997 cohorts and less than or equal to the fifth centile on the Movement Assessment Battery for Children-Second Edition for the 2005 cohort.

Results: Motor impairment was more likely in children born EP and/or ELBW compared with children born at term for all epochs. There was a significant increase in motor impairment in EP and/or ELBW children over the 3 eras, from 23% in 1991-1992 and 26% in 1997 to 37% in 2005 (χ²_trend = 10.2; P = .001). This was due to an increase in non-CP motor impairment (13% in 1991 to 1992; 15% in 1997; 26% in 2005; χ²_trend = 12.5; P < .001), not CP (11% in 1991 to 1992; 11% in 1997; 12% in 2005).

Conclusions: The rate of motor impairment in EP and/or ELBW children assessed at 8 years of age increased between eras, an increase caused by non-CP motor impairment.